how to provide static ip address for external system to whitelist my ec2 in private subnet ip address in aws?

If your EC2 instance is in a private subnet, it doesn’t have a public IP and can't be directly accessed from the internet. However, if you want external systems to whitelist a fixed public IP to allow outbound communication from your EC2 (e.g., for APIs, SFTP, databases), you have two sure-shot options:

Option 1: Use a NAT Gateway with an Elastic IP (Recommended for Scalability) Create an Elastic IP Go to EC2 → Elastic IPs → Allocate new address.

Create a NAT Gateway in a public subnet

Attach the Elastic IP to the NAT Gateway.

Ensure the subnet has a route to the internet via the Internet Gateway.

Route private subnet traffic to the NAT Gateway

In your private subnet’s route table, add:

Destination: 0.0.0.0/0 Target: <your NAT Gateway> Test outbound traffic Any EC2 instance in the private subnet will now go out via the NAT Gateway, and appear from the Elastic IP. Share this Elastic IP with external parties to whitelist.

Option 2: Use a Proxy or Bastion Host with EIP (For Inbound Access Needs) If the external system needs to initiate the connection (e.g., SSH, HTTP calls to your EC2), do the following:

Launch a bastion host or reverse proxy in a public subnet, attach an Elastic IP.

Set up routing, security groups, and possibly a proxy tool (like NGINX, HAProxy, or SSM port forwarding) to forward or relay traffic to the private EC2.

Give the Elastic IP of the bastion to external systems to whitelist.

Generic Security Notes Always restrict NAT/Bastion security groups to the required IPs and ports. Use AWS Systems Manager (SSM) for secure access to private EC2s when possible; there is no need for bastions or public IPs.